Explosive foil initiators generally include plural components, namely a substrate having a bridge, a flyer overlying the bridge, a barrel, and a sleeve containing a secondary explosive. Normally, the flyer is comprised of a polyimide material and the sleeve is comprised of a rigid material, particularly stainless steel.
The present EFI designs may have difficulty operating at elevated temperatures (200° C. and above). It has been demonstrated that at higher temperatures the explosive can actually expand longitudinally into the barrel from the sleeve, which in effect shortens the length the barrel. Secondly, the flyer can become ductile, causing a tearing of the material as opposed to a clean fracture.